The wheeled vehicles, which are an evolution of the infamous Segway “personal transportation device”, are too unsafe to ride on the road, but too dangerous to ride on the pavement, according to legislation. As a result, they are only legal to use on land that is private property, and only with the landowner’s permission, the CPS says.

The guidance, which was initially released for Segway scooters, points out that since self-balancing scooters are powered vehicles they are illegal to ride on the pavement under section 72 of the Highway Act 1835. In Scotland, where the act does not apply, they are still illegal to ride on the pavement under the Roads (Scotland) Act 1984.

In fact, Simon Benson of hoverboard distributor Ghetto Gadgets argues that the legal clarification could boost the profile of the gadgets. “If the authorities give any impression that the use of hoverboards in some circumstances is unlawful, then I expect sales to soar.

“Clearly customers need to take advice, but millennials are not going to take kindly to the authorities using a law that pre-dates the penny-farthing to tell them what they can or can’t do on the streets of Britain”.

Hoverboards remain legal to use in private spaces with the permission of the landowner, but some of the biggest private estates have confirmed that they too maintain a ban of the use of the device. While the gadgets are a common sight in Westfield’s Stratford City shopping complex, the centre confirmed that they are are not allowed on the premises. The Canary Wharf estate said that any motorised vehicle would only be allowed on the roadways, in effect banning hoverboards there too.

London’s Royal Parks, however, said that generally, hoverboards aren’t banned but may be restricted by signage in certain areas. A spokesperson added “We pride ourselves on ensuring the Royal Parks are open to everyone.”

The self-balancing scooters are just the latest in a long series of low-powered electronic transportation gadgets to hit the market, following “monopods” (self-balancing unicycles), electric skateboards, and Segways themselves. But owing to a perfect storm of cheap Chinese manufacturing, celebrity endorsements and a good dose of luck, the scooters are the first to become a genuine craze.

The Hovertrax, one of the first to hit the market in the US, started life as a Kickstarter campaign in May 2013 and raised $85,000 from 162 backers. Its first units arrived in December 2014, but just two months later, in February 2015, a conflict arose between Hovertrax (which owns a patent for “a two wheel, self-balancing persoanl vehical) and a rival manufacturer, IO Hawk. Now, there are tens of brands, all largely importing the same base units from Chinese manufactuers and making cosmetic improvements before selling them on to consumers.

Despite the popular nickname, self-balancing scooters do not actually hover. But real hoverboards are about to hit the market, with Arx Pax, an American start-up, offering the devices for $10,000 a piece. The magnetic technology they use requires an all-metal surface to hover over, meaning that they are unlikely to be useable anywhere other than specially prepared private land, but if they ever do hit public streets, a new legal question will be raised: it may be illegal to use a hoverboard on the pavement, but what about a few inches above it?